RF distance
Which factors will effect communication distance ?
F:315MHz, Modulation:ASK
Please give me some advices .
For line-of-sight communication. The factors that will affect the range of communication are "frequency" "Tx power" "Rx sensitivity" "Antenna gain" "Transmission line loss" and "the heigh of antenna".
Don't forget background noise, receiver dynamic range, IF filtering, error correction coding.
Hi pico,biff44:
My details as follow,
The Rx sensitivity :-105dbm
The Tx power:0dbm
The antennna length :1/2 λ
My hardware and decode way are same with other,but their distance is able to reach 100m in car .
According to the free space path loss formula:
Ploss = 20*log((4*Pi*d)/Lambda)
where:
d = distance in meters
Lambda = wavelength in meters
Pi = 3.14
That means at 315 MHz the path loss at 100m is 62dB.
Assuming a 0dBd antenna gain on both sides, and ignoring other loss factors and interferers, your link budget should be ok for a proper communication using ASK.
It remains a margin of 43dB (105-62) that you can allocate for noise, error correction, interferers or whatever.
Check if your TX antenna is proper matched. There you can lose a lot of dB?s.
Considering various practically available solutions for filters and other circuitry. The main factor that would decide your communication range would be ANTENNA parameters like power transmitted and effieciency of antenna.
So work on antenna section.